[unreadable] Radioimmunoguided surgery holds great promise for the sensitive detection of cancer, which can translate to improved clinical benefit by allowing more accurate determination of the extent of disease. The intra-operative surgical probe is a valuable tool providing critical intra-operative data in cancer surgery. Probes must detect a range of radiopharmaceuticals that utilize different radioisotopes. The proposed intra-operative surgical probe with enhanced performance aims to improve localization of radioisotope over the photon energy range from 18 to 511 keV. Positron emission tomography (PET) can detect tumors early and reveal the extent to which the cancer has spread. Similar to the imaging procedures used in cancer localization, 18F-FDG can be used in the surgical arena to locate sites of cancer. This has not been possible because no current surgical probe has effectively imaged 511 keV. It has increased sensitivity for high-energy photons for use with positron emitting radionuclides such as 18F. It has superior low energy and proximity performance for depth identification for 99mTc. The probe uses a solid-state detector and a multi-segmented collimator with electronics to detect coincidence events between segments. When completed the Phase I results will demonstrate the feasibility and expected performance of the multi-function surgical probe and its suitability for use in proximity identification for 99mTc applications and for use with 511 keV photons. We will determine the fundamental performance parameters for detecting 511 keV photons and for proximity response with this probe. [unreadable] [unreadable] Current probes only provide two-dimensional localization of sources with no information on the depth of the source. Our probe design utilizes information from multiple segments of a thick solid-state detector. The surgical probe described herein provides the ability to operate over the energy range from 18 to 511 keV. Utilizing information from the simultaneous emissions of 140keVgamma rays and 18-20 keV x-rays from 9gmTcwe will provide source proximity information. [unreadable] [unreadable]